Non-volatile memories are those memories that are capable of retaining the data stored in their cells for a significantly long time, usually in excess of ten years, after they were disconnected from a power supply. The use of floating gates in non-volatile memory, and in particular in metal-oxide semiconductor field effect transistors (MOSFET) is common in the art. Digital devices include Electrically Programmable Read Only Memory (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), and Flash memories. Digital devices typically have a range of a data or other information corresponding generally to a logic value of “0” or a logic value of “1”. These devices have a large range of application in both embedded and stand-alone components. However, the requirements from such memory may vary significantly depending on the specific application in which such memory is to be used. For example, the dominant requirement may be the storage of large quantities of data and emphasize the smallest possible cell size. In other cases, the amount of data to be stored is quite small and it is important to ensure that the additional costs that are required for enabling a circuit to be a non-volatile memory are minimized.
Information stored in a memory cell is usually sensed by using a sense amplifier capable of detecting small levels of voltage and translating them to a larger voltage swing, hence separating low voltages that are associated with one logical level from a high voltage associated with another logical level. A differential sense amplifier is capable of sensing small differences between two nodes, each having a potential respective to a common line.
Some previous technologies suggest multiple methods and circuits of testing non-volatile memories as well as methods for acceleration of such tests. However, these previous technologies fail to show methods of testing dual polarity non-volatile memories, i.e., memories that store in a single non-volatile memory cell the data in both a positive and a negative polarity, enabling the sensing of the data in a manner that leaves significant margin for successful operation of the non-volatile memory cell.